Apparatus for the production of cellulose



Jan. 12, LANGEN APPARATUS FOR THE PRODUCTION OF CELLULOSE' Filed May 24, 1954 2 Sheets-Sheet 1 5 I E 1 I Im/eman' Jan. 12, 1960 E. LANGEN 2,920,697

APPARATUS FOR THE PRODUCTION OF CELLULOSE Filed May 24, 1954 2 Sheets-Sheet 2 Inventor? WW MM my/ APPARATUS FOR THE PRODUCTION OF CELLULOSE Eugen Langen, Braunschweig-Gliesmarode, Germany, assignor to Braunschweigische Maschinenbauanstalt Alrtiengesellschaft Application May 24, 1954, Serial No. 431,924 Claims priority, application Germany March 28, 1953 1 Claim. (Cl. 162-237) Hitherto the production of cellulose required large expensive apparatus and, in particular, complicated and integration takes place first and is followed by washing,

if desired in the same container,*the discharge for the crude cellulose and the outlet for the black liquor being located at opposite ends of the container.

It is advisable for the container to be divided into different regulatable heating zones which allow the temperature course over the container to be controlled by means of the lye preferably in such a manner that at the ends of the container the temperature is below 100 C. whereas in the reaction region the maximum reaction temperature is attained.

A useful form of construction is so designed that preferably regulatable connections are provided for the individual zones of the container in the region of reaction for feeding'the treatment agents, such as water,

' black liquor, acid or alkaline chemicals, steam or the like.

At the same time it is possible to construct the extensions of the connections leading into the interior of the container as bafiies for the material to be treated, which extensions project, for example, into gaps provided in a worm or the like feeding the material.

Furthermore the device according to the invention is preferably provided with a pressure regulating device which maintains a constant overpressure in the container,

preferably by means of the fresh water feed. The construction according to the invention can be still further improved by connecting to one end of the container a pump, preferably an adjustable pump, for

supplying the material to be treated and the feeding capacity of this pump preferably regulates the quantity of black liquor directly orindirectly removed from the container.

According to a further development of the apparatus, the outlet of the disintegrated material is pressure-regulated, the control being preferably dependent upon the inof example in the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of the container, Fig. 2 is a graph showing the temperature curve in the different parts of the container, and

United States Farm Fig. 3 shows the whole plant in a diagrammatic view.

In a tower 1 about 24 metres in height, a worm 2 is mounted which fills the entire cross-sectional area of the tower and through which the cellulose feeds in upward direction. This worm is driven through the intermediary of a transmission gearing 3 by a motor 4 installed at the top end of the tower.

To the lower end of the tower a feed conduit 5 is connected which communicates by way of a pump 6 with a mixer 8 equipped with a stirring mechanism 7.

This is connected to the outlet 11 for black liquor at the bottom of the tank. The valve 9 is controlled from the float 9" through a leverage 9 that is connected to the mixer after the manner of a connecting pipe in a housing of known type. According to the liquid level in the mixer 8 and the housing 9 the passage of fluid through valve 9 is regulated. The shredded material is fed from a storage container 15 on to a distributing device 14 in the form of a jigger which leads to a weigh-band 13 which discharges the material in to a hopper 12 leading to the mixer.

A fresh water feed conduit 19 in which a valve operable manually or otherwise 18 is fitted, is connected to the upper end of the tower and a preferably horizontal delivery worm 16 leads to a chute 17. Distributed over the greater part of the height of the tower are feed pipes 20 for the black liquor, 21 for acid or alkaline chemicals, such as caustic soda or sulphite solution, gases such as S0 or the like, and 22 for steam. These feed pipes 20, 21, 22, which are preferably provided with regulating valves 23, project into the interior of the tower into corresponding gaps 24 in the worm 2 serving as feeding device and act as baflles.

The feed pipe 20 for the black liquor is connected by a conduit 25 in which a regulating valve 26 and a pump 27 are fitted, to the regulating device of the mixer 8 on the one hand and to the outflow conduit 11 for the black liquor leading from the lower end of the tower on the other hand.

The feeds and temperatures of the material to be treated, the water, black liquor, chemicals and steam are so chosen that by their combined effect temperatures below C. are maintained at the upper and lower ends of the tower whereas in the intermediate reaction region the maximum reaction temperatures are attained, as indicated in the graph, Fig. 2.

The material to be treated, for example chopped straw, rice straw, wood, crushed sugar cane and other annual or perennial vegetable substances are supplied from the storage container 15 by the distributing device 14, the weigh-band 13 and the hopper 12 to the mixer 8 into which black liquor is simultaneously fed from the tower outlet 11 through the conduit 10 and regulating device 9. The regulating device 9 adapts the feed output of the pump 6, which is preferably adjustable, to the actual withdrawal. The mixer 7 ensures a uniform mixing of the material with the liquid in a state fit for feeding and conveys the mixture by means of the pump 6 into the lower end of the tower, whence it is conveyed in upward direction in the tower by means of the worm 2.

At the same time the washing liquid, pure water, is introduced into the upper end of the tower 1 at a temperature below 100 C. through the regulating valve 18 and conduit 19 at a pressure of about 4 atmospheres. By thus tempering the washing liquid unnecessary steam generation and as a consequence technical difficulties resulting therefrom are avoided.

Black liquor is added to the washing liquid through the tube 20 at the height of the tower where the cellulose is almost entirely decomposed, and lower down the chemicals, such as concentrated caustic soda or sulphite solution, are introduced through the pipes 21 which are Patented Jan. 12, 1960 so distributed that a constant pressure is maintained in the tower. By the steam feed in particular, which is effected through the pipes 22 with the regulating valves 23, the temperature in the region of reaction in the tower is controlled substantially in accordance with the curve shown in Fig. 2, which shows that the temperatures at the two ends of the tower are below 100 C. while in the region of reaction the temperature approximates the maximum temperature X C. which varies in individual cases.

The material produced in this manner, after its continuous passage through the various zones of treatment in the tower, is finally delivered on to the chute 17 by means of the worm 16.

I claim:

Apparatus for the production of cellulose comprising a vertically disposed tower, a segmental worm screw extending substantially the length of said tower for moving the material from the bottom to the top, nozzle 4. means for injecting fluids into said tower at the spaces between the worm segments with such means extending into the space between the worm segments to serve as bafiles, 'means for controlling the entrance of fluid at various points along said tower, and means to maintain a higher temperature in the mid-portion of said tower than at the ends thereof, the temperature in the midportions being above the boiling point of Water and the temperature at the bottom and top being below the boiling point of water, and screw-feed means at the top of said tower for removing the processed material.

References Cited in the file of this patent UNITED STATES PATENTS 2,709,652 Plunguian May 31, 1955 FOREIGN PATENTS 122,608 Sweden 1948 

